Display panel and manufacturing method thereof

ABSTRACT

Disclosed are a display panel and a manufacturing method thereof. The display panel comprises: a substrate, a plurality of conductive units and a plurality of Mini LEDs. A material of the conductive units is conductive ink, and the conductive ink comprises a prepolymer, a monomer, a conductive filler and a photoinitiator. The viscosity of the conductive ink itself is employed to adsorb the Mini LEDs to improve the transfer accuracy of the Mini LEDs and to prevent the weak adsorption between the Mini LEDs and the conductive units, which affects the electrical connection between the conductive units and the Mini LEDs.

FIELD OF THE INVENTION

The present application relates to a display technology field, and moreparticularly to a display panel and a manufacturing method thereof.

BACKGROUND OF THE INVENTION

In the current STM (Surface Mounted Technology) process of mini lightemitting diodes (Mini LEDs), solder paste is generally applied to thebonding pads of the Mini LEDs to realize the electrical connectionbetween the Mini LEDs and the substrate.

Since the patterns on the substrate are relatively dense, the metaltraces are interlaced and easily scratched. In the solder paste process,direct contact processes, such as screen printing and roller stamping,are generally used. The screen board of the screen printing has a largercontact depth with the substrate, and the pressure of the scraper of thescreen printing is too large, which will scratch the metal traces. Theuneven surface of the scraper of the screen printing, the roller of theroller stamping or the substrate will easily cause the contact area ofthe substrate with the scraper or the roller to become smaller, causinglocal stress concentration. It is easy to cause cracks in the insulatinglayer inside the substrate to cause a short circuit in direct contactbetween the gate layer and the source and drain layer. Moreover, theunsteady speed of the scraper or the roller can easily cause the uneventhickness of the solder paste, which may cause the Mini LED to be easilylifted up at the thicker part of the solder paste during placement,which will eventually cause the Mini LED to shift.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a display panel anda manufacturing method thereof, which can solve problems of metal tracesbeing easily scratched and short circuits between metal traces in thesolder paste process in the existing Mini LED bonding process.

For solving the aforesaid problems, the present invention provides adisplay panel, comprising: a subsrate; a plurality of conductive units,arranged on the substrate at intervals; and a plurality of Mini LEDs(mini light emitting diodes), arranged on a side of the conductive unitsaway from the substrate at intervals; each of the Mini LEDs iselectrically connected to the conductive units; wherein a material ofthe conductive units is conductive ink, and the conductive ink comprisesa prepolymer, a monomer, a conductive filler and a photoinitiator.

Furthermore, the prepolymer comprises one of more of Hyperbranchedurethane acrylate and Epoxy acrylate.

Furthermore, the monomer comprises one or more of trimethylolpropanetriacrylate and pentanediol diacrylate.

Furthermore, the photoinitiator is isopropyl thioxanthone.

Furthermore, the conductive filler comprises one or more of sphericalnano silver powder and flake-shaped nano silver powder.

Furthermore, a ratio of the monomer to the prepolymer ranges from 1:(1-2).

Furthermore, a ratio of the epoxy acrylate to the hyperbranched urethaneacrylate ranges from 2: (2-4).

Furthermore, the display panel further comprises a plurality ofconductive elements, arranged between the substrate and the conductiveunits at intervals, and arranged in one-to-one correspondence with theconductive units.

For solving the aforesaid problems, the present invention provides amanufacturing method of a display panel, comprising steps of: providinga substrate; coating conductive ink on the substrate, and patterning theconductive ink by using photolithography to form conductive ink unitsarranged on the substrate at intervals; wherein the conductive inkcomprises a prepolymer, a monomer, a conductive filler and aphotoinitiator; arranging a plurality of Mini LEDs (mini light emittingdiodes) on a side of the conductive ink units away from the substrate atintervals, and each of the Mini LEDs is electrically connected to theconductive ink units; and curing the conductive ink units to formconductive units.

Furthermore, a thickness of the conductive ink ranges from 20 μm to 30μm.

The present invention employs prepolymers, monomers, conductive fillersand photoinitiators to form conductive ink, and then employs conductiveink to prepare conductive units to achieve electrical connection betweenMini LEDs and conductive elements. The viscosity of the conductive inkitself is employed to adsorb the Mini LEDs to improve the transferaccuracy of the Mini LEDs and to prevent the weak adsorption between theMini LEDs and the conductive units, which affects the electricalconnection between the conductive units and the Mini LEDs. Theconductive unit is made by coating and photolithography, and the gapbetween adjacent conductive units can be controllably adjusted tofurther improve the transfer accuracy of Mini LEDs.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the presentapplication, the following figures will be described in the embodimentsare briefly introduced. It is obvious that the drawings are only someembodiments of the present application, those of ordinary skill in thisfield can obtain other figures according to these figures without payingthe premise.

FIG. 1 is a structure diagram of a display panel of the presentinvention;

FIG. 2 is a structure diagram of substrate of the display panel of thepresent invention;

FIG. 3 is a diagram of manufacturing steps of the display panel of thepresent invention;

FIG. 4 is a plan view diagram of the display panel after coatingconductive ink on the substrate among the conductive elements;

FIG. 5 is a plan view diagram of the conductive ink of FIG. 4 beingpatterned to form conductive ink units;

FIG. 6 is a cross-sectional view diagram taken along line A-A of FIG. 5;

FIG. 7 is a structure diagram of disposing the Mini LEDs on theconductive ink units;

FIG. 8 is a structure diagram of removing the transferring substrate ofFIG. 6 and curing the conductive ink units.

Components symbol description:

100 display panel;  1 substrate;  2 conductive element;  3 conductiveunit;  4 Mini LED;  5 transferring substrate;  11 base substrate; 12buffer layer;  13 thin film transistor layer; 14 planarization layer; 31 conductive ink; 32 conductive ink unit.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, the preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying appended figuresof the specification, so as to fully introduce the technical content ofthe present invention to those skilled in the art, so as to demonstratethat the present invention can be implemented by illustrations, so thatthe technical content disclosed by the present invention is clearer formaking it easier for those skilled in the art to understand how toimplement the present invention. However, the invention may be achievedin many different forms of embodiments, and the scope of the inventionis not limited to the embodiments set forth herein. The description ofthe following embodiments is not intended to limit the scope of thepresent invention.

The terms of up, down, front, rear, left, right, interior, exterior,side, etcetera mentioned in the present invention are merely directionsin appended figures. The directional terms used herein are employed toexplain and describe the present invention, but not to limit theprotection scope of the present invention. In the appended figures,components with the same structure are denoted by

the same numerals, and components with similar structures or functionsare denoted by similar numerals. In addition, for ease of understandingand description, the size and thickness of each component shown in theappended figures are arbitrarily shown, and the present invention doesnot limit the size and thickness of each component.

As shown in FIG. 1 , this embodiment provides a display panel 100. Thedisplay panel 100 comprises: a substrate 1, a plurality of conductiveelements 2, a plurality of conductive units 3 and a plurality of MiniLEDs 4.

As shown in FIG. 2 , the substrate 1 comprises a base substrate 11, abuffer layer 12, a thin film transistor layer 13 and a planarizationlayer 14.

A material of the base substrate 11 is one or more of glass, polyimide,polycarbonate, polyethylene terephthalate and polyethylene naphthalate.Therefore, the base substrate 11 can possess better impact resistanceand can effectively protect the display panel 100.

The buffer layer 12 is arranged on a surface of the base substrate 11.The buffer layer 12 mainly functions as a buffer, and a material of thebuffer layer 12 comprises one or more of SiNx and SiOx.

The thin film transistor layer 13 is arranged on a surface of the bufferlayer 12 away from the base substrate 11. The thin film transistor layer13 is mainly employed to control the electronic conversion of pixels andprovide circuit support for the display panel 100. The thin filmtransistor layer 13 comprises an active layer, a first insulating layer,a gate layer, an interlayer insulating layer, a source and drain layerand other film layers, which will not be repeated here.

The planarization layer 14 is arranged on a surface of the thin filmtransistor layer 13 away from the base substrate 11. The planarizationlayer 14 mainly functions for planarization, and provides a planarsurface for the preparation of the upper film layer, and theplanarization layer 14 can also function for buffer. A material of theplanarization layer 14 comprises one or more of acrylic photoresist,silicon photoresist and polyimide photoresist.

The plurality of conductive elements 2 are arranged on the substrate 1at intervals. In this embodiment, a material of the conductive elements2 is Indium tin oxide (ITO). In other embodiments, the conductiveelements 2 can also be made of other conductive materials.

The plurality of conductive units 3 is arranged on a side of theconductive units 2 away from the substrate 1 at intervals and arrangedin one-to-one correspondence with the conductive elements 2.

The plurality of Mini LEDs 4 is arranged on a side of the conductiveunits 3 away from the substrate 1 at intervals. Each of the Mini LEDs 4comprises a first electrode 41 and a second electrode 42. The firstelectrode 41 and the second electrode 42 are both electrically connectedto one conductive unit 3.

A material of the conductive units 3 is conductive ink 31, and theconductive ink 31 comprises a prepolymer, a monomer, a conductive fillerand a photoinitiator.

The prepolymer comprises one of more of Hyperbranched urethane acrylateand Epoxy acrylate. A ratio of the epoxy acrylate to the hyperbranchedurethane acrylate ranges from 2: (2-4). In this embodiment, theprepolymer comprises Hyperbranched urethane acrylate and Epoxy acrylate.The ratio of the epoxy acrylate to the hyperbranched urethane acrylateis 2:3.

The monomer comprises one or more of trimethylolpropane triacrylate andpentanediol diacrylate. A ratio of the monomer to the prepolymer rangesfrom 1: (1-2). In this embodiment, the ratio of the monomer to theprepolymer is 1:1.5.

In this embodiment, the photoinitiator is isopropyl thioxanthone (ITX).The content of the photoinitiator is 10% of the content of theconductive ink excluding the conductive filler. The conductive fillercomprises one or more of spherical nano silver powder and

flake-shaped nano silver powder. In this embodiment, the conductivefiller comprises spherical nano silver powder and flake-shaped nanosilver powder. The ratio of the spherical nano silver powder to theflake-shaped nano silver powder is 3:7.

Therefore, the conductive ink 31 formed by mixing the prepolymer,monomer, conductive filler and photoinitiator of this embodimentpossesses better conductivity, higher adhesion, shorter photo-curingtime and lower resistivity. Specifically, the curing time range of theconductive ink 31 of this embodiment is 6 s-7 s, and the resistivity canreach 10-60 Ωm.

In conclusion, prepolymers, monomers, conductive fillers andphotoinitiators are employed to form conductive ink 31, and then theconductive ink 31 is employed to prepare conductive units 3 to achieveelectrical connection between Mini LEDs 4 and conductive elements 2. Theviscosity of the conductive ink 31 itself is employed to adsorb the MiniLEDs 4 to improve the transfer accuracy of the Mini LEDs 4 and toprevent the weak adsorption between the Mini LEDs 4 and the conductiveunits 3, which affects the electrical connection between the conductiveunits 3 and the Mini LEDs 4.

As shown in FIG. 3 to FIG. 8 , the present invention provides amanufacturing method of a display panel 100, comprising steps of: S1,providing a substrate 1; S2, forming conductive elements 2 at intervalson the substrate 1; S3, coating conductive ink 31 on surfaces ofconductive elements 2 away from the substrate 1 and on the substrate 1among adjacent conductive elements 2, and patterning the conductive ink31 by using photolithography to remove the conductive ink 31 on thesubstrate 1 among the adjacent conductive elements 2, then to formconductive ink units 32 at intervals and in one-to-one correspondencewith the conductive elements 2; wherein the conductive ink 31 comprisesa prepolymer, a monomer, a conductive filler and a photoinitiator; S4,arranging a plurality of Mini LEDs 4 on a side of the conductive units 3away from the substrate 1 at intervals, and each of the Mini LEDs 4 iselectrically connected to the conductive ink units 32; and S5, curingthe conductive ink units 32 to form conductive units 3.

As shown in FIG. 4 , A thickness of the conductive ink 31 ranges from 20μm to 30 μm. In this embodiment, the thickness of the conductive ink 31is 25 μm.

As shown in FIG. 5 and FIG. 6 , by using photolithography to remove theconductive ink 31 on the substrate 1 among the adjacent conductiveelements 2, the conductive ink units 32 at intervals and in one-to-onecorrespondence with the conductive elements 2 are formed. The gapbetween adjacent conductive ink units 32 can be controllably adjusted tofurther improve the transfer accuracy of Mini LEDs 4.

As shown in FIG.7, the Mini LEDs 4 are prepared on the transferringsubstrate 5. Then, the Mini LEDs 4 and the transferring substrate 5 as awhole are hot-pressed or cold-pressed on the surface of the conductiveink units 32 on the side away from the substrate 1. The viscosity of theconductive ink units 32 themselves is employed to adsorb the Mini LEDs 4to improve the transfer accuracy of the Mini LEDs 4 and to prevent theweak adsorption between the Mini LEDs 4 and the conductive ink units 32,which affects the electrical connection between the conductive ink units32 and the Mini LEDs 4.

As shown in FIG. 8 , the transferring substrate 5 is stripped andremoved first, and then the conductive ink units 32 are cured byultraviolet light (UV light) to form the conductive units 3.

The display panel and the manufacturing method thereof provided by theembodiments of the present application are described in detail asaforementioned, and the principles and implementations of the presentapplication have been described with reference to specificillustrations. The description of the foregoing embodiments is merelyfor helping to understand the technical solutions of the presentapplication and the core ideas thereof; meanwhile, those skilled in theart will be able to change the specific embodiments and the scope of theapplication according to the idea of the present application. Inconclusion, the content of the specification should not be construed aslimiting the present application.

What is claimed is:
 1. A display panel, comprising: a substrate; aplurality of conductive units, arranged on the substrate at intervals;and a plurality of Mini LEDs (mini light emitting diodes), arranged on aside of the conductive units away from the substrate at intervals; eachof the Mini LEDs is electrically connected to the conductive units;wherein a material of the conductive units is conductive ink, and theconductive ink comprises a prepolymer, a monomer, a conductive fillerand a photoinitiator.
 2. The display panel according to claim 1, whereinthe prepolymer comprises one of more of Hyperbranched urethane acrylateand Epoxy acrylate.
 3. The display panel according to claim 1, whereinthe monomer comprises one or more of trimethylolpropane triacrylate andpentanediol diacrylate.
 4. The display panel according to claim 1,wherein the photoinitiator is isopropyl thioxanthone.
 5. The displaypanel according to claim 1, wherein the conductive filler comprises oneor more of spherical nano silver powder and flake-shaped nano silverpowder.
 6. The display panel according to claim 1, wherein a ratio ofthe monomer to the prepolymer ranges from 1: (1-2).
 7. The display panelaccording to claim 2, wherein a ratio of the epoxy acrylate to thehyperbranched urethane acrylate ranges from 2: (2-4).
 8. The displaypanel according to claim 1, further comprising: a plurality ofconductive elements, arranged between the substrate and the conductiveunits at intervals, and arranged in one-to-one correspondence with theconductive units.
 9. A manufacturing method of a display panel,comprising steps of: providing a substrate; coating conductive ink onthe substrate, and patterning the conductive ink by usingphotolithography to form conductive ink units arranged on the substrateat intervals; wherein the conductive ink comprises a prepolymer, amonomer, a conductive filler and a photoinitiator; arranging a pluralityof Mini LEDs (mini light emitting diodes) on a side of the conductiveink units away from the substrate at intervals, and each of the MiniLEDs is electrically connected to the conductive ink units; and curingthe conductive ink units to form conductive units.
 10. The manufacturingmethod according to claim 9, wherein a thickness of the conductive inkranges from 20 μm to 30 μm.